Regulating apparatus associated with hydraulic servo-control and follow-up acting devices



OctQ 3, 1961 J. SZYDLOWSKI 3,002,502

REGULATING APPARATUS ASSOCIATED WITH HYDRAULIC SERVO-CONTROL AND FOLLOW-UP ACTING DEVICES Filed Feb. 12, 1958 United States Patent 3,002,502 REGULATING APPARATUS ASSOCIATED WIT HYDRAULIC SERVO-CONTROL AND FOLLOW- UlP ACTING DEVICES Joseph Szydlowski, Bordes, Basses-Pyrenees, France Filed Feb. 12, 1958, Ser. No. 714,798 Claims priority, application France Feb. 19, 1957 2 Claims. (Cl. 121-42) The present invention relates to regulating devices of the type associated with hydraulic servo-control means.

To ensure the stability of a regulating device some kind of follow-up dependence must be provided between the control movement obtained in this device and the parameter to be regulated. Generally, in systems involving the operation of a regulating device associated with hydraulic servo-control means, the follow-up action is performed through either a rod linkage or purely mechanical means, or composite hydraulic and mechanical means.

In view of simplifying the construction of regulating devices of this general character while improving their reliability and fidelity, it is the essential object of the present invention to provide a regulating device with hydraulic servo-control and follow-up action means characterised by the fact that it comprises a distributing slide-valve for the liquid under pressure utilized for actuating a servocontrol piston driving in turn the regulation control device, the opposite ends of said distributing slide-valve being subjected to the actions of a member responsive in turn to the parameter to be adjusted and of another member for presetting the value at which this parameter is to be adjusted, respectively, a hydraulic device adapted to subject said slide-valve, under transient operating conditions and against the member of which the action is preponderant to a force opposite to the action of said last member and generated by the difference existing between the servocontrol liquid pressure and the liquid pressure existing at the outlet of said distributing slide-valve, and another hydraulic device for neutralizing the action of this force under stabilized operating conditions.

According to an advantageous form of embodiment of this invention, the control piston is hydraulically connected to a temporary follow-up acting piston reciprocable within a cylinder with slots adapted to initiate the return of said follow-up acting piston to its stabilized position after its operation, the pressure of the liquid interconnecting said two pistons being transmitted to that end of the distributing slide-valve on which the member for pre-setting the parameter value to be adjusted is applied while the pressure of the liquid contacting the other face of said follow-up acting piston is applied to the end of the distributing slide-valve distributor subjected to the action of the member responsive to the parameter to be adjusted, the liquid masses in contact with the non-hydraulically interconnected faces of the control and follow-up acting pistons being connected through said distributing slide-valve to the inlet and outlet of said slidevalve, respectively, or vice-versa, according as the parameter value to be adjusted is higher or lower than its value at the moment considered. An adjustable compensation valve with laminar flow interconnects the two faces of the temporary follow-up acting piston in order positively to drive this piston along the final portion of its return stroke to its position of equilibrium under stabilized operating conditions.

Other features and advantages of this invention will become apparent as the following description proceeds with reference to the accompanying drawing illustrating diagrammatically by way of example a typical embodiment of the invention to illustrate the manner in which the same may be carried out in the practice. In the drawings:

ice

FIGURE 1 is a diagrammatic sectional view showing a regulating device with hydraulic servo-control and followup action means constructed according to the teachings of this invention.

FIGURE 2 is a similar view illustrating the practical application of the regulating device of FIG. 1 to the fuel feed system of an internal combustion engine.

In the embodiment illustrated in FIG. 1 the regulating device comprises a distributor 1 having slidably mounted in its body a distributing slide-valve 2 axially movable in a sleeve 3 mounted in a bore 4 formed in said body 1. The slide-valve 2 is formed with shoulders 5, 6, 7 and 8 of same diameter of which the intermediate ones 6, 7 constitute the distributing members co-acting, on the one hand, with a duct 9 formed in the body 1 and connected through a pipe line 10 to the delivery port of a pump P adapted to deliver a liquid under pressure, for example oil, and, on the other hand, with ducts 11, 12, 13 and 14 formed in said' distributor body. In the inoperative position of the slide-valve 2 the duct 9 lies between the shoulders 6 and 7, the duct 11 between the shoulders 5 and 6, the duct 14 between the shoulders 7 and 8, and the ducts 12, 13 are obturated by the shoulders 6 and 7 respectively.

The movement of the slide-valve 2 is controlled by a push rod 15 engaging the end 16 of the slide-valve and connected to the member responsive to the parameter to be adjusted. This movement may also be controlled by the operator by means of a screw 17 acting through the medium of a spring 18 on the other end 19 of the slidevalve.

Thus, the operator may preset the parameter value to be regulated. p

In order to prevent any frictional contacts from interfering with the smooth sliding movement or" the slidevalve, the sleeve 3 is rotatably driven by a toothed wheel 20 meshing with a small hydraulic motor 21 actuated by the very pressure of the liquid utilized in the servo-control device and fed to this motor through a duct 22 branched off the duct 9, the liquid returning to the pump through a duct 23 and a pipe line 24. a

The distributor described hereabove is used for regulating a servo-control piston 25 mounted in a chamber 26 formed in a block 27. This control piston is connected at 28 through a rod 29 to the regulation control member (not shown); the chamber 26 is connected through a duct 30 with another chamber 31 formed in the block 27 and having longitudinal slots 32a, in which another piston constituting the temporary follow-up acting piston 32 is slidably mounted; this servo-piston 32 is disposed between two opposed springs 33, 34 of same force. From the duct 30 are branched off two ducts 35, 38 leading the one 35 through a duct 36 to the chamber 37 of the distributor which receives the end 19 of the slide-valve 2, and the other 38 into a chamber 40 containing a compensation valve 41 with laminar flow adjustable by means of a screw 42 against the resilient force of a spring 43. This chamber 40 is connected through a duct 44 and a pipe line 45 to the chamber-46 receiving the other end 16 of slide-valve 2. Another duct 47 connects the upper face of the temporary follow-up acting piston 32 to the duct 44, and a pipe line 48 branched 0T1 the pipe line 45 leads to the duct 13 of the distributor. The chamber 26 in which the control piston is slidably mounted is connected through a pipe line 49 to the duct 12 of the distributor. The latter has its ducts 11 and 14 connected through pipe lines 50 and 51 to the suction side of pump P. p

The arrangement described hereinabove operates as follows: I

Under stabilized operating conditions the slide-valveof the distributor is positioned as illustrated in FIG.- "1

wherein the liquid delivered from the pump P through the pipe line and duct 9 cannot escape through either of the ducts 12 or 13 obturated by the shoulders 6 and 7 of the slide-valve.

When, due to the action of the member responsive to the parameter to be adjusted, the slide-valve 2 ismoved by the push-rod 15 to the left, the liquid under pressure delivered through the pipe line 10 and duct 9 escapes through the duct 12 and pipe line 49, thereby moving the control piston to the left and causing a corresponding control action to be exerted on the control member associated therewith. As a consequence of this movement of control piston 25, the fluid is forced through the duct 30. Part of this fluid acts on the lower face of the temporary follow-up acting piston 32 and the latter is moved upwards against the resistance of the upper spring 33 while relieving the lower spring 34. The liquid in the chamber 31 which contacts the upper face of this piston 32 escapes from said chamber through ducts 47 and 44. Said liquid flows through the pipe line 45 and is directed partly through the pipe line 48, open duct 13, duct 14 and pipe line 5 1 to the suction side of the pump, and partly into the chamber 46. On the other hand, the part of chamber 31 underlying the piston 32 communicates through the duct 35 and pipe line 36 with the chamber 37 opposite to the chamber 46 with respect to the slide-valve. Due to the differential compression between springs 33 and 34 a differential pressure is created between the liquid pressures to which the upper and lower faces of the temporary follow-up acting piston 32 are subjected. This slide-valve 2 is thus subjected at its ends 16, 19 and therefore at its shoulders 5 and 8 of same diameter to the same pressures respectively as upper and lower faces of piston 32, the direction of the resultant force being opposite to that of the initial displacement of this slidevalve. Therefore, a follow-up action is obtained. Due to the provision of slots 32a, the temporary follow-up acting piston 32 initiates its return movement to its position of equilibrium.

Similarly, when the slide-valve is displaced tothe right as a function of the preset value of the parameter to be regulated, the delivery side of the pump is caused to communicate with the upper face of the follow-up acting piston 32 and the liquid pressure is thus transmitted to the chamber 46. This piston 32 moves downwards in the chamber 31 while compressing the spring 34 and relieving the spring 33 and drives the control piston 25 to the right to actuate the control member accordingly. As a consequence of the displacement, of this control piston 25 to the right, the liquid forced by this piston escapes through the pipe line 49 and now open duct 12 to the suction side of the pump. At thetsame time, the chamber 37 is subjected to the pressure of the liquid existing between the pistons 32 and 25, i.e. to a pressure corresponding to that at the delivery side of the pump.

The direction of the force resulting from the pressures exerted in chambers 46 and 37 respectively is opposite to that of the initial movement of the slide-valve 2. Consequently, the follow-up action is maintained.

To avoid any permanent irregularity in the operation of the device the temporary follow-up acting piston 32 is definitely restored to its position of equilibrium by the action of the compensation valve 41 with laminar flow whereby the pressure differential existing between the two faces of piston 32 and therefore between the chambers 37 and 46 is neutralized or reduced to zero.

FIGURE 2 illustrates diagrammatically the application of the regulating device described hereinabove to the specific case of the fuel feed system of an internal combustion engine. In the example illustrated the slide valve 2 is rotatably mounted in a fixed sleeve 3 and adapted to be driven at a relatively low speed with respect to that of the engine from a small liquid turbine 52 mounted in the chamber 46. The member responsive to the parameter to be regulated, for example the number of revolutions of the engine in this case, consists of a member 53 mounted in axial alignment with the slide-valve 2 and rotatably driven from the engine; this member 53 has pivoted thereon inertia masses 54 adapted to act upon a cup-shaded member '55 mounted for loose rotation, through the medium of a ball-bearing 56 on the corresponding end of the slide-valve 2. The liquid which is stirred up in chamber 46 by the rotating inertia masses 5 4 induces the rotary motion of turbine 52 at relatively low speed without any mechanical connection between said turbine and the engine. The rotation of the inertia masses in the liquid filling chamber 46 and that of slidevalve 2 increase the efficiencies of said inertia masses and slide-valve.

Under permanent speed conditions, the inertia masses 54 are urged by the slide-valve 2 to their position shown in FIG. 2, whereas in transient operating conditions since inertia masses 54 are adapted to pivot about their pivot pins 57 in one or the other direction, according as the engine speed varies or the operator presets a rotational speed other than that obtaining under permanent speed conditions. The operator transmits the value of the preset rotational speed with the assistance of a device comprising a control lever 58 of first order the free end of which is controlled by a cam (not shown); this lever 58 is pivoted on a screw-threaded member 59 on which a toothed wheel 60 is screwed, the position of this wheel 60 on the member 59 being adjustable manually by rotating another toothed wheel 61 in one or the other direction, the assembly transmitting the preset values to the other end of the slide-valve 2 through the intermediary of a spring 62.

The control piston 25 is coupled to a needle valve 63 movable in a chamber 64 inserted in the fuel feed duct 65 leading to the engine; this needle valve 63 co-acts with a valve seat 66 to more or less throttle the fuel passage and therefore the output of the fuel flowing in this duct.

The operation of the device illustrated in FIG. 2 is similar to that of the device shown in FIG. 1 and described hereinabove; therefore, it is not necessary to explain this operation again.

It is to be understood that the invention is not limited to the herein shown and described specific embodiment but contemplates all such modifications and variants thereof as fall fairly within the scope of the appended claims. Particularly the rotary movement of the slidevalve or of its sleeve might be generated by any known means.

What I claim is:

1. In an apparatus for regulating the fuel feed of an internal combustion engine and of the type comprising a distributing slide-valve adapted to feed with a liquid under pressure, on the one hand, a servo-control piston mechanically connected to a regulation control device for said fuel feed and, on the other hand, a temporary follow-up acting piston hydraulically connected to said servo-control piston, according as the prevailing number of revolutions of the engine is lower or higher than the number of revolutions to be adjusted, the two faces of said temporary follow up acting piston being interconnected through an adjustable restricted valve providing a laminar flow and being respectively connected to two chambers respectively housing the ends of said slide-valve; the improvement which comprises an assembly adapted to preset the value at which the fuel feed, and therewith the number of revolutions of the engine, is to be adjusted and bearing on the end of said slide-valve in the chamber receiving the pressure of the liquid interconnecting the servo-control and follow-up acting pistons, a member mounted in axial alignment with the slide-valve and rotatably driven by the engine, inertia masses pivoted on said member, acting upon the corresponding end of the slidevalve and housed in the other chamber, and means car- 5 ried by said slide-valve and housed in said other chamber for rotatably driving said slide-valve at relatively slow speed under the action of the liquid which is stirred up by said inertia masses in said other chamber whereby the efiiciencies of said inertia masses and slide-valve are increased.

2. A device, according to claim 1, wherein the assembly comprises a control lever, a screw-threaded member on which said lever is pivoted, and, in the other chamber, a toothed wheel screwed on said screw-threaded member, a spring interposed between said toothed wheel and the corresponding end of the slide-valve, and second toothed wheel meshing with the first one and manually controlled for adjusting the position of the first toothed wheel on said screw-threaded member.

References Cited in the file of this patent UNITED STATES PATENTS Drake Aug. 9, 1949 Drake Aug. 9, 1949 Parker Aug. 9, 1949 Avery Aug. 28, 1951 Walthers Jan. 8, 1952 Walther-s June 10, 1952 Parker Dec. 30, 1952 Whitehead et a1 Aug. 4, 1953 Parker Feb. 23, 1954 Parker July 31, 1956 Moog Oct. 23, 1956 Whitehead Feb. 25, 1958 Clarke et a1. Nov. 3, 1959 

